Computer network server systems and related components are typically housed in support structures, such as racks or chassis, configured to house and to assimilate the functions of a plurality of component devices. System chassis provide efficient organization for the plurality of components for ease of access, serviceability, expandability, power distribution, cooling, etc.
These system chassis generally are housed in a computer server room, which hosts many computers and servers that all require fans to keep the systems cooled. Cooling fans come integrated with systems or are installed in larger combination systems. Alternatively, cooling fans can also be installed outside the systems. When cooling fans are installed outside systems, typically, they are installed in the same system chassis with the systems they are designed to cool. Cooling fans emit vibration with varying frequencies and intensities (or magnitudes), depending on the fan models and the running speeds. If the vibration of the cooling fans on the system chassis at a particular fan speed resonates with the system chassis, destructive amplification of vibration could cause disk drives in the system chassis to fail or to operate at less than optimal performance. Due to increases in density and reductions in size of hard disk drives (HDDs), current read/write magnetic heads are expected to read/write a track with less than about 20 nanometers in width. In addition, the read/write magnetic heads float at about 7 nanometers above the disk surface. Due to these tight tolerances, the internal vibrational resonance in the system chassis, caused by cooling fans, can cause the read/write function of hard disk drives to fail.
As a consequence, what is needed is a method to detect fan speed(s) that would result in the internal vibrational resonance with system chassis to avoid running the cooling fan at or near the identified speed(s). Avoiding operation of the cooling fans near the fan speed(s) that would cause internal vibrational resonance improves the performance hard disk drives.